Computer viruses, computer worms, Trojan horses, and other malicious computer elements, also known as malware, are typically a concern for a business enterprise or other suitable entity that operates using a computer network. These malicious computer elements are often distributed throughout the computer network, either knowingly or unknowingly, using an email application or another application that communicates messages over the computer network. For example, a user may knowingly or unknowingly distribute a malicious computer element by sending emails to one or more other users in the enterprise that include the malicious computer element. As another example, due to a malicious computer element, a user system may automatically send emails that propagate the malicious computer element throughout a computer network. These malicious computer elements often fake certain information in communications such that the true source of the communication is hidden or misrepresented. For example, a malicious computer element may alter the “To” and “From” fields in a Multipurpose Internet Mail Extension (MIME) header of emails, such that the true source of the email is hidden or misrepresented.